Electrode with integrated ceramic separator

ABSTRACT

An electrode including an integrated separator for use in an electrochemical device may include one or more active material layers, and a separator layer comprising inorganic particles. An interlocking region may couple the separator layer to an adjacent active material layer. In some examples, the interlocking region may include interlocking fingers formed by an interpenetration of active material particles of the active material layers with ceramic particles of the separator.

CROSS-REFERENCES

This application claims the benefit under 35 U.S.C. § 119(e) of thepriority of U.S. Provisional Patent Application Ser. No. 62/830,301,filed Apr. 5, 2019, the entirety of which is hereby incorporated byreference for all purposes.

FIELD

This disclosure relates to electrochemical cells. More specifically, thedisclosed embodiments relate to electrodes having separators.

INTRODUCTION

Environmentally friendly sources of energy have become increasinglycritical, as fossil fuel-dependency becomes less desirable. Mostnon-fossil fuel energy sources, such as solar power, wind, and the like,require some sort of energy storage component to maximize usefulness.Accordingly, battery technology has become an important aspect of thefuture of energy production and distribution. Most pertinent to thepresent disclosure, the demand for secondary (i.e., rechargeable)batteries has increased. Various combinations of electrode materials andelectrolytes are used in these types of batteries, such as lead acid,nickel cadmium (NiCad), nickel metal hydride (NiMH), lithium ion(Li-ion), and lithium ion polymer (Li-ion polymer).

SUMMARY

The present disclosure provides systems, apparatuses, and methodsrelating to an electrode having an integrated ceramic separator.

In some embodiments, an electrochemical cell electrode having anintegrated separator layer may include: an electrochemical cellelectrode including a current collector substrate and an electrodematerial composite layered onto the current collector substrate; aseparator layer including a plurality of inorganic particles, disposedsuch that the electrode material composite is between the separatorlayer and the current collector substrate; and an interlocking regionadhering the separator layer to the electrode material composite, theinterlocking region including a non-planar interpenetration of theseparator layer and the electrode material composite in which firstfingers of the electrode material composite interlock with secondfingers of the separator layer.

In some embodiments, an electrochemical cell electrode having anintegrated separator layer may include: an electrochemical cellelectrode having a current collector substrate coupled to one or moreactive material layers each comprising a respective plurality of activematerial particles; and a separator layer in direct contact with anadjacent layer of the one or more active material layers, such that theone or more active material layers are between the separator layer andthe current collector substrate, the integrated separator layerincluding a plurality of ceramic particles; wherein an interlockingregion secures the separator layer to the adjacent active materiallayer, the interlocking region including a non-planar boundary betweenthe separator layer and the adjacent active material layer, such thatthe adjacent active material layer and the separator layer areinterpenetrated.

In some embodiments, a method of manufacturing an electrode for anelectrochemical cell may include: causing a current collector substrateand an electrode material composite dispenser to move relative to eachother; and coating at least a portion of the current collector substratewith an electrode material composite and a separator material to producean electrochemical cell electrode, using the dispenser, wherein coatingincludes: dispensing one or more active material layers each comprisinga slurry of active material composite onto the current collectorsubstrate using one or more respective first orifices of the dispenser;and dispensing a separator layer onto the one or more active materiallayers while the active material composite is wet, using one or moresecond orifices of the dispenser, such that the one or more activematerial layers are between the separator layer and the currentcollector substrate, the separator layer including a plurality ofceramic particles; wherein an interpenetrating boundary is formedbetween the separator layer and an adjacent one of the one or moreactive material layers.

Features, functions, and advantages may be achieved independently invarious embodiments of the present disclosure, or may be combined in yetother embodiments, further details of which can be seen with referenceto the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of an illustrative electrochemicalcell.

FIG. 2 is a sectional view of an illustrative electrode including anintegrated ceramic separator layer.

FIG. 3 is a sectional view of an interlocking region included within theillustrative electrode of FIG. 2 .

FIG. 4 is a sectional view of an illustrative integrated ceramicseparator coating with a multilayered electrode.

FIG. 5 is a flow chart depicting steps of an illustrative method formanufacturing electrodes in accordance with aspects of the presentdisclosure.

FIG. 6 depicts an example of an electrode material composite on asubstrate web, prior to blanking.

FIG. 7 depicts an example of an electrode material composite on asubstrate web configured in lanes.

FIG. 8 depicts an example of an electrode material composite implementedwith a skip coating manufacturing process.

FIG. 9 is a sectional view of an illustrative electrode undergoing acalendering process in accordance with aspects of the presentdisclosure.

FIG. 10 is a schematic diagram of an illustrative manufacturing systemsuitable for manufacturing electrodes and electrochemical cells of thepresent disclosure.

FIG. 11 is a schematic diagram of an illustrative stacked cell format inaccordance with aspects of the present disclosure.

FIG. 12 is a schematic diagram of an illustrative stacked cell formatwith protruding tabs, in accordance with aspects of the presentdisclosure.

FIG. 13 is a schematic diagram of an illustrative stacked cell formatwith tape applied to cathode layers, in accordance with aspects of thepresent disclosure.

DETAILED DESCRIPTION

Various aspects and examples of electrodes including an integratedceramic separator, as well as related systems and methods, are describedbelow and illustrated in the associated drawings. Unless otherwisespecified, an electrode in accordance with the present teachings, and/orits various components, may contain at least one of the structures,components, functionalities, and/or variations described, illustrated,and/or incorporated herein. Furthermore, unless specifically excluded,the process steps, structures, components, functionalities, and/orvariations described, illustrated, and/or incorporated herein inconnection with the present teachings may be included in other similardevices and methods, including being interchangeable between disclosedembodiments. The following description of various examples is merelyillustrative in nature and is in no way intended to limit thedisclosure, its application, or uses. Additionally, the advantagesprovided by the examples and embodiments described below areillustrative in nature and not all examples and embodiments provide thesame advantages or the same degree of advantages.

This Detailed Description includes the following sections, which followimmediately below: (1) Definitions; (2) Overview; (3) Examples,Components, and Alternatives; (4) Advantages, Features, and Benefits;and (5) Conclusion. The Examples, Components, and Alternatives sectionis further divided into subsections A through F, each of which islabeled accordingly.

Definitions

The following definitions apply herein, unless otherwise indicated.

“Substantially” means to be more-or-less conforming to the particulardimension, range, shape, concept, or other aspect modified by the term,such that a feature or component need not conform exactly. For example,a “substantially cylindrical” object means that the object resembles acylinder, but may have one or more deviations from a true cylinder.

“Comprising,” “including,” and “having” (and conjugations thereof) areused interchangeably to mean including but not necessarily limited to,and are open-ended terms not intended to exclude additional, unrecitedelements or method steps.

Terms such as “first”, “second”, and “third” are used to distinguish oridentify various members of a group, or the like, and are not intendedto show serial or numerical limitation.

“AKA” means “also known as,” and may be used to indicate an alternativeor corresponding term for a given element or elements.

“Coupled” means connected, either permanently or releasably, whetherdirectly or indirectly through intervening components.

Directional terms such as “up,” “down,” “vertical,” “horizontal,” andthe like should be understood in the context of the particular object inquestion. For example, an object may be oriented around defined X, Y,and Z axes. In those examples, the X-Y plane will define horizontal,with up being defined as the positive Z direction and down being definedas the negative Z direction.

“Providing,” in the context of a method, may include receiving,obtaining, purchasing, manufacturing, generating, processing,preprocessing, and/or the like, such that the object or materialprovided is in a state and configuration for other steps to be carriedout.

Overview

In general, an electrode including an integrated separator in accordancewith the present teachings may include an electrode layer having aplurality of active material particles adhered together by a firstbinder, and a separator layer including a plurality of ceramic particlesadhered together by a second binder. The electrode further includes aninterlocking region (AKA an interphase region) disposed between andadhering the electrode layer and the separator layer, wherein theinterlocking region comprises a non-planar boundary between theelectrode layer and the separator layer.

The electrode layer may include a first active material layer includinga first plurality of active material particles. In some embodiments, theelectrode layer further includes a second active material layerincluding a second plurality of active material particles, defining amultilayer architecture. The first and second active material layers mayhave different porosities, different material chemistries, differentactive material particle sizes, and/or any alternative material propertyaffecting electrode function. The electrode layer may have a thickness,measured as a distance perpendicular to the plane of a current collectorto which the electrode is adhered and an opposing (AKA upper) surface ofthe electrode layer.

The separator layer may include a first plurality of inorganicparticles. In some embodiments, the inorganic particles may be ceramicssuch as aluminum oxide (i.e., alumina (α-Al2O3)), corundum, calcined,tabular, synthetic boehmite, silicon oxides or silica, zirconia, and/orthe like. The separator may have any suitable range of thicknesses(e.g., 1 μm-50 μm). The separator layer may be configured such that theseparator isolates the electrode (e.g. anode or cathode) from anadjacent electrode included within an electrochemical cell, whilemaintaining permeability to a charge carrier such as a lithium-ioncontaining electrolyte.

The interlocking region may include a non-planar interpenetration of theelectrode layer and the separator layer, in which first fingers orprotrusions of the first layer interlock with second fingers orprotrusions of the second layer. The interlocking layer or interfaceregion created by the interpenetration of the electrode layer and theseparator layer may reduce interfacial resistance and increase ionmobility through the electrode. The integrated separator may alsoprevent crust formation on active material surface of electrode, whichmay impede flow of ions.

In general, a method of manufacture for an electrode including anintegrated separator may include extruding composite materials on aconductive substrate. An integrated separator layer may be extruded onthe active material layer, either simultaneously or, in some examples,after drying. In some embodiments, simultaneous, near-simultaneous, orotherwise wet-on-wet extrusion of the integrated separator onto theactive material layer may be utilized to create interpenetrating fingerstructures at a boundary between the separator and active materiallayers, as a result of turbulent flow at the boundary. Thismanufacturing process may eliminate the need to manufacture or obtain anextra component (e.g., polyolefin separator) and may reduce overallmanufacturing costs.

Whereas known methods manufacture a separator for the cell independentlyfrom the electrodes, the separator described herein is manufactured asan integral part of at least one of the electrodes. Accordingly, theprocess of manufacturing an electrode with a separator layer issimplified. Moreover, the nonplanar interface between the separator andthe active material of the electrode provides several benefits overknown examples.

Examples, Components, and Alternatives

The following sections describe selected aspects of exemplary electrodesincluding integrated ceramic separators, as well as related systemsand/or methods. The examples in these sections are intended forillustration and should not be interpreted as limiting the scope of thepresent disclosure. Each section may include one or more distinctembodiments or examples, and/or contextual or related information,function, and/or structure.

A. Illustrative Electrochemical Cell

This section describes an electrochemical cell including an electrode ofthe present teachings. The electrochemical cell may be any bipolarelectrochemical device, such as a battery (e.g. lithium-ion battery,secondary battery).

Referring now to FIG. 1 , an electrochemical cell 100 is illustratedschematically in the form of a lithium-ion battery. Electrochemical cell100 includes a positive and a negative electrode, namely a cathode 102and an anode 104. The cathode and anode are sandwiched between a pair ofcurrent collectors 106, 108, which may comprise metal foils or othersuitable substrates. Current collector 106 is electrically coupled tocathode 102, and current collector 108 is electrically coupled to anode104. The current collectors enable the flow of electrons, and therebyelectrical current, into and out of each electrode. An electrolyte 110disposed throughout the electrodes enables the transport of ions betweencathode 102 and anode 104. In the present example, electrolyte 110includes a liquid solvent and a solute of dissolved ions. Electrolyte110 facilitates an ionic connection between cathode 102 and anode 104.

Electrolyte 110 is assisted by a separator 112, which physicallypartitions the space between cathode 102 and anode 104. Separator 112 isliquid permeable, and enables the movement (flow) of ions withinelectrolyte 110 and between the two electrodes. As described furtherbelow, separator 112 may be integrated within one or both of cathode 102and anode 104. In some embodiments, for example, separator 112 comprisesa layer of ceramic particles applied to a top surface of an electrode(i.e., cathode 102 or anode 104), such that the ceramic particles ofseparator 112 are interpenetrated or intermixed with active materialparticles of cathode 102 or anode 104. In some embodiments, electrolyte110 includes a polymer gel or solid ion conductor, augmenting orreplacing (and performing the function of) separator 112.

Cathode 102 and anode 104 are composite structures, which compriseactive material particles, binders, conductive additives, and pores(void space) into which electrolyte 110 may penetrate. An arrangement ofthe constituent parts of an electrode is referred to as amicrostructure, or more specifically, an electrode microstructure.

In some examples, the binder is a polymer, e.g., polyvinylidenedifluoride (PVdF), and the conductive additive typically includes ananometer-sized carbon, e.g., carbon black or graphite. In someexamples, the binder is a mixture of carboxyl-methyl cellulose (CMC) andstyrene-butadiene rubber (SBR). In some examples, the conductiveadditive includes a ketjen black, a graphitic carbon, a low dimensionalcarbon (e.g., carbon nanotubes), and/or a carbon fiber.

In some examples, the chemistry of the active material particles differsbetween cathode 102 and anode 104. For example, anode 104 may includegraphite (artificial or natural), hard carbon, titanate, titania,transition metals in general, elements in group 14 (e.g., carbon,silicon, tin, germanium, etc.), oxides, sulfides, transition metals,halides, and chalcogenides. On the other hand, cathode 102 may includetransition metals (for example, nickel, cobalt, manganese, copper, zinc,vanadium, chromium, iron), and their oxides, phosphates, phosphites, andsilicates. The cathode may also include alkalines and alkaline earthmetals, aluminum, aluminum oxides and aluminum phosphates, as well ashalides and chalcogenides. In an electrochemical device, activematerials participate in an electrochemical reaction or process with aworking ion to store or release energy. For example, in a lithium-ionbattery, the working ions are lithium ions.

Electrochemical cell 100 may include packaging (not shown). For example,packaging (e.g., a prismatic can, stainless steel tube, polymer pouch,etc.) may be utilized to constrain and position cathode 102, anode 104,current collectors 106 and 108, electrolyte 110, and separator 112.

For electrochemical cell 100 to properly function as a secondarybattery, active material particles in both cathode 102 and anode 104must be capable of storing and releasing lithium ions through therespective processes known as lithiating and delithiating. Some activematerials (e.g., layered oxide materials or graphitic carbon) fulfillthis function by intercalating lithium ions between crystal layers.Other active materials may have alternative lithiating and delithiatingmechanisms (e.g., alloying, conversion).

When electrochemical cell 100 is being charged, anode 104 acceptslithium ions while cathode 102 donates lithium ions. When a cell isbeing discharged, anode 104 donates lithium ions while cathode 102accepts lithium ions. Each composite electrode (i.e., cathode 102 andanode 104) has a rate at which it donates or accepts lithium ions thatdepends upon properties extrinsic to the electrode (e.g., the currentpassed through each electrode, the conductivity of the electrolyte 110)as well as properties intrinsic to the electrode (e.g., the solid statediffusion constant of the active material particles in the electrode;the electrode microstructure or tortuosity; the charge transfer rate atwhich lithium ions move from being solvated in the electrolyte to beingintercalated in the active material particles of the electrode; etc).

During either mode of operation (charging or discharging) anode 104 orcathode 102 may donate or accept lithium ions at a limiting rate, whererate is defined as lithium ions per unit time, per unit current. Forexample, during charging, anode 104 may accept lithium at a first rate,and cathode 102 may donate lithium at a second rate. When the secondrate is lesser than the first rate, the second rate of the cathode wouldbe a limiting rate. In some examples, the differences in rates may be sodramatic as to limit the overall performance of the lithium-ion battery(e.g., cell 100). Reasons for the differences in rates may depend on anenergy required to lithiate or delithiate a quantity of lithium-ions permass of active material particles; a solid state diffusion coefficientof lithium ions in an active material particle; and/or a particle sizedistribution of active material within a composite electrode. In someexamples, additional or alternative factors may contribute to theelectrode microstructure and affect these rates.

B. Illustrative Electrode with Integrated Separator

Operation of an energy storage device under demanding conditions at thelimits of an electrode's capabilities requires accommodating stressesinduced by volume expansion (swelling) and contraction during thecharging and discharging of battery electrodes. This may lead tostructural and functional challenges, as an electrochemical cellincluding the electrode may have one or more layers, each swelling orcontracting at different rates during battery charging and discharging.More specifically, active material layers of electrodes may expand andcontract during battery use, while inert separator particles may remainconstant in size. Polyolefin separators, commonly used in lithium-ionbatteries, may shrink while an adjacent electrode expands, increasingthe risk that a battery including the electrode will short during use.

Ensuring continued structural integrity of an electrode-separatorinterface is necessary to prevent shorting between cathodes and anodesincluded in the battery, introducing several design considerations. Amechanical integrity or coherence of the electrochemical cell must bemaintained so that an electrode and an adjacent separator remainmechanically stable and adhered to each other. Additionally, aninterface between the active material layers and the separator shouldnot block or inhibit a flow of ions through the electrochemical cell. Inthe case of an anode, the interface between the layers should not createregions of increased densification. Such increased densification canresult in solid electrolyte interphase (SEI) buildup at the interfacebetween the layers that subsequently blocks pores and induces lithiumplating. These issues present challenges which must be addressed in theproduction of an electrochemical cell with a separator.

With reference to FIG. 2 , a single layer electrode 200 having anintegrated ceramic separator is shown. Electrode 200 is an example of ananode or cathode suitable for inclusion in an electrochemical cell,similar to cathode 102 or anode 104, described above. Electrode 200includes a current collector substrate 260 and an electrode materialcomposite 270 layered onto the current collector substrate. Electrodematerial composite 270 includes an active material layer 202 and anintegrated separator layer 204, with an interlocking region 210 disposedbetween active material layer 202 and integrated separator layer 204.Interlocking region 210 comprises a non-planar boundary between activematerial layer 202 and integrated separator layer 204, configured todecrease interfacial resistance between the layers and reduce lithiumplating on the electrode layer.

Active material layer 202 is disposed on and directly in contact withcurrent collector substrate 260. Active material layer 202 includes aplurality of first active material particles 240 adhered together by afirst binder. Active material layer 202 may further include a conductiveadditive mixed with the active material particles. In some examples, thebinder is a polymer, e.g., polyvinylidene difluoride (PVdF), and theconductive additive typically includes a nanometer-sized carbon, e.g.,carbon black or graphite. In some examples, the binder is a mixture ofcarboxyl-methyl cellulose (CMC) and styrene-butadiene rubber (SBR). Insome examples, the conductive additive includes a ketjen black, agraphitic carbon, a low dimensional carbon (e.g., carbon nanotubes),and/or a carbon fiber.

In some examples, electrode 200 is an anode suitable for inclusionwithin an electrochemical cell. In the case of such an anode, activematerial particles 240 may comprise graphite (artificial or natural),hard carbon, titanate, titania, transition metals in general, elementsin group 14 (e.g., carbon, silicon, tin, germanium, etc.), oxides,sulfides, transition metals, halides, and chalcogenides.

In some examples, electrode 200 is a cathode suitable for inclusionwithin an electrochemical cell. In the case of such a cathode, activematerial particles 240 may comprise transition metals (for example,nickel, cobalt, manganese, copper, zinc, vanadium, chromium, iron), andtheir oxides, phosphates, phosphites, and silicates. The cathode activematerial particles may also include alkalines and alkaline earth metals,aluminum, aluminum oxides and aluminum phosphates, as well as halidesand chalcogenides.

As depicted in FIG. 2 , integrated separator layer 204 may be layeredonto active material layer 202, and may include a plurality of ceramicparticles 250 adhered together by a second binder. Although ceramicparticles 250 are referred to as ceramics, particles 250 may compriseany suitable inorganic material or materials, including ceramics such asaluminum oxide (i.e., alumina (α-Al₂O₃)), corundum, calcined, tabular,synthetic boehmite, silicon oxides or silica, zirconia, and/or the like.Ceramic particles 250 may be electrically non-conductive.

Ceramic particles 250 may have a greater hardness than active materialparticles 240. As a result, separator layer 204 may have a higherresistance to densification and lower compressibility than activematerial layer 202. In some examples, the second binder is a polymer,e.g., polyvinylidene difluoride (PVdF). Integrated separator layer 204may have any thickness suitable for allowing ionic conduction whileelectrically insulating the electrode. In some examples, separator layer204 may have a thickness between one μm and fifty μm.

Integrated separator layer 204 may comprise varying mass fractions ofinorganic particles (e.g., ceramic particles) and varying mass fractionsof binders and other additives. In some examples, the separator layer isbetween 50% and 99% inorganic material. In other examples, the separatorlayer is greater than 99% inorganic material and less than 1% binder. Inthe examples having greater than 99% inorganic material, the electrodemay be manufactured in a similar fashion to electrodes with separatorlayers having lower percentages of inorganic material, optionallyfollowed by ablation of excess binder during post-processing.

In other examples, the separator layer is less than 50% inorganicmaterial and greater than 50% binder, by mass. In these cases, thebinder may comprise a coblocked polymer such as a polyamide,polyethylene, polypropylene, polyolefin, and/or any combination ofsuitable polymers with a porous structure. The binder may comprise afirst and second polypropylene layer and a polyethylene layerintermediate the polypropylene layers. This high-binder contentconfiguration may function as a “shutdown” mechanism for the electrode.For example, the polyethylene layer may melt or collapse at hightemperatures (e.g., in a fire), thus stopping ionic and electrodeconduction and thereby improving device safety. On the other hand, thehigh-binder embodiments may decrease calendering advantages seen inseparator layers with higher fractions of inorganic material.

In some examples, an additional polyolefin separator layer may be addedon a top surface of the integrated separator layer.

Interlocking region 210 includes a non-planar boundary between activematerial layer 202 and separator layer 204. Active material layer 202and separator layer 204 have respective, three-dimensional,interpenetrating fingers 214 and 216 that interlock the two layerstogether, forming a mechanically robust interface that is capable ofwithstanding stresses, such as those due to electrode expansion andcontraction, and separator shrinking. Additionally, the non-planarsurfaces defined by fingers 214 and fingers 216 represent an increasedtotal surface area of the interface boundary, which may provide reducedinterfacial resistance and may increase ion mobility through theelectrode. Fingers 214 and 216 may be interchangeably referred to asfingers, protrusions, extensions, projections, and/or the like.Furthermore, the relationship between fingers 214 and 216 may bedescribed as interlocking, interpenetrating, intermeshing,interdigitating, interconnecting, interlinking, and/or the like.

Fingers 214 and fingers 216 are a plurality of substantially discreteinterpenetrations, wherein fingers 214 are generally made up of theelectrode's active material particles 240 and fingers 216 are generallymade up of ceramic separator particles 250. The fingers arethree-dimensionally interdigitated, analogous to an irregular form ofthe stud-and-tube construction of Lego bricks. Accordingly, fingers 214and 216 typically do not span the electrode in any direction, such thata cross section perpendicular to that of FIG. 2 will also show anon-planar, undulating boundary similar to the one shown in FIG. 2 .Interlocking region 210 may alternatively be referred to as a non-planarinterpenetration of active material layer 202 and separator layer 204,including fingers 214 interlocked with fingers 216.

As shown in FIG. 3 , although fingers 214 and 216 may not be uniform insize or shape, the fingers may have an average or typical length 218. Insome examples, length 218 of fingers 214 and 216 may fall in a rangebetween two and five times the average particle size of the first activematerial layer or the separator layer, whichever is smaller. In someexamples, length 218 of fingers 214, 216 may fall in a range between sixand ten times the average particle size of the first active materiallayer or the separator layer, whichever is smaller. In some examples,length 218 of fingers 214 and 216 may fall in a range between eleven andfifty times the average particle size of the first active material layeror the separator layer, whichever is smaller. In some examples, length218 of fingers 214 and 216 may be greater than fifty times the averageparticle size of the first active material layer or the separator layer,whichever is smaller.

In some examples, length 218 of fingers 214 and 216 may fall in a rangeof approximately five hundred to approximately one thousand nanometers.In some examples, length 218 of fingers 214 and 216 may fall in a rangeof approximately one to approximately five μm. In some examples, length218 of fingers 214 and 216 may fall in a range between approximately sixand approximately ten μm. In another example, length 218 of fingers 214and 216 may fall in a range between approximately eleven andapproximately fifty μm. In another example, length 218 of fingers 214and 216 may be greater than approximately fifty μm.

In the present example, a total thickness 224 of interlocking region 210is defined by the level of interpenetration between the two electrodematerial layers (first active material layer 202 and separator layer204). A lower limit 226 may be defined by the lowest point reached byseparator layer 204 (i.e. by fingers 216). An upper limit 228 may bedefined by the highest point reached by first active material layer 202(i.e. by fingers 214). Total thickness 224 of interlocking region 210may be defined as the separation or distance between limits 226 and 228.In some examples, the total thickness of interlocking region 210 mayfall within one or more of various relative ranges, such as betweenapproximately 200% (2×) and approximately 500% (5×), approximately 500%(5×) and approximately 1000% (10×), approximately 1000% (10×) andapproximately 5000% (50×), and/or greater than approximately 5000% (50×)of the average particle size of the first active material layer or theseparator layer, whichever is smaller.

In some examples, total thickness 224 of interlocking region 210 mayfall within one or more of various absolute ranges, such as betweenapproximately 500 and one thousand nanometers, one and approximately tenμm, approximately ten and approximately fifty μm, and/or greater thanapproximately fifty μm.

In the present example, first active material particles 240 in firstactive material layer 202 have a distribution of volumes which have agreater average than an average volume of ceramic particles 250 inseparator layer 204 i.e., a larger average size. In some examples, firstactive material particles 240 have a collective surface area that isless than the collective surface area of ceramic particles 250.

In the present example, first active material particles 240 and ceramicparticles 250 are substantially spherical in particle morphology. Inother examples, one or both of the plurality of particles in either thefirst active material layer or the separator layer may have particlemorphologies that are: flake-like, platelet-like, irregular,potato-shaped, oblong, fractured, agglomerates of smaller particletypes, and/or a combination of the above.

When particles of electrode portion 200 are lithiating or delithiating,electrode portion 200 remains coherent, and the first active materiallayer and the separator layer remain bound by interlocking region 210.In general, the interdigitation or interpenetration of fingers 214 and216, as well as the increased surface area of the interphase boundary,function to adhere the two zones together.

In one example, electrode portion 200 is a portion of a cathode includedin a lithium ion cell. In this example during charging of the lithiumion cell, first active material particles 240 delithiate. During thisprocess, the active material particles may contract, causing activematerial layer 202 to contract. In contrast, during discharging of thecell, the active material particles lithiate and swell, causing activematerial layer 202 to swell.

In an alternate example, electrode portion 200 is a portion of an anodeincluded in a lithium ion cell. In this example, during charging of thelithium ion cell, first active material particles 240 lithiate. Duringthis process, the active material particles may swell, causing activematerial layer 202 to swell. In contrast, during discharging of thecell, first active material particles 240 delithiate and contract,causing contraction of active material layer 202.

In either of these examples, during swelling and contracting, electrodeportion 200 may remain coherent, and active material layer 202 andseparator layer 204 remain bound by interlocking region 210. Thisbonding of the active material layer and separator layer may decreaseinterfacial resistance between the layers and maintain mechanicalintegrity of an electrochemical cell including the electrode.

Interlocking region 210 may comprise a network of fluid passagewaysdefined by active material particles, ceramic particles, binder,conductive additives, and/or additional layer components. These fluidpassages are not hampered by calendering-induced changes in mechanicalor morphological state of the particles due to the non-planar boundaryincluded in the interlocking region. In contrast, a substantially planarboundary is often associated with the formation of a crust layer uponsubsequent calendering. Such a crust layer is disadvantageous as it cansignificantly impede ion conduction through the interlocking region.Furthermore, such a crust layer also represents a localized compactionof active material particles that effectively result in reduced porevolumes within the electrode. This may be an issue of particularimportance for anodes, as solid electrolyte interphase (SEI) filmbuildup on active material particles clogs pores included within theelectrode at a quicker rate, leading to lithium plating, decreasingsafety and cycle life of the electrode.

An anode with integrated ceramic separator according to the presentdisclosure may experience additional benefits over alternate electrodeforms. As anodes may include active material particles withcomparatively larger average particle size than other electrodes (e.g.cathodes), anodes may experience increased compressibility fromsimultaneous calendering with an integrated separator layer. As ceramicseparator particles may have a hardness greater than a hardness of theanode active material particles and therefore a greater resistance todensification during a calendering process, the ceramic separator layermay transfer compressive loads to the anode layer disposed beneath theceramic separator layer.

C. Illustrative Multi-Layered Electrode with Integrated Separator

FIG. 4 is an illustrative multi-layered electrode 300 including a firstactive material layer 302, a second active material layer 304, and aseparator layer 306. Second active material layer 304 may be disposedadjacent to a current collector substrate 320. First active materiallayer 302 may be layered on top of second active material layer 304.Separator layer 306 may be layered on top of first active material layer302. First active material layer 302 may include a plurality of firstactive material particles adhered together by a first binder. Secondactive material layer 304 may include a plurality of second activematerial particles adhered together by a second binder. The first andsecond active material particles may be substantially similar to activematerial particles 240, described above. Separator layer 306 may includea plurality of inorganic particles adhered together by a third binder.The inorganic particles may be substantially similar to ceramicparticles 250, described above.

A first interlocking region 308 is formed between separator layer 306and first active material layer 302. A second interlocking region 310 isformed between first active material layer 302 and second active layer304.

First interlocking region 308 may include a non-planar boundary betweenfirst active material layer 302 and separator layer 306. First activematerial layer 302 may have a first plurality of fingers 312 extendingtoward separator layer 306. Separator layer 306 may have a secondplurality of fingers 314. First interlocking region 308 may include aninterpenetration of fingers 312 and fingers 314, which may bind thefirst active material layer and the separator layer together.

Second interlocking region 310 may include a non-planar boundary betweenfirst active material layer 302 and second active material layer 304.First active material layer 302 may have a third plurality of fingers316 extending toward current collector substrate 320. Second activematerial layer 304 may have a fourth plurality of fingers 318. Secondinterlocking region 310 may include an interpenetration of fingers 316and 318, which may bind the first and second active material layerstogether. The configuration of the fingers in first interlocking region308 and second interlocking region 310 is substantially similar to theconfiguration of the fingers in interlocking region 210 of FIG. 2 ,described above.

Additional aspects and features of electrodes including integratedceramic separators are presented below, without limitation, as a seriesof interrelated paragraphs.

A0. An electrochemical cell electrode having an integrated separatorlayer, the electrode comprising:

an electrochemical cell electrode including a current collectorsubstrate and an electrode material composite layered onto the currentcollector substrate;

a separator layer including a plurality of inorganic particles, disposedsuch that the electrode material composite is between the separatorlayer and the current collector substrate; and

an interlocking region adhering the separator layer to the electrodematerial composite, the interlocking region including a non-planarinterpenetration of the separator layer and the electrode materialcomposite in which first fingers of the electrode material compositeinterlock with second fingers of the separator layer.

A1. The electrode of A0, wherein the electrode material compositecomprises a first layer including a plurality of first active materialparticles, and a second layer including a plurality of second activematerial particles.

A2. The electrode of A0 or A1, wherein a mass fraction of the inorganicparticles in the separator layer is greater than 50%.

A3. The electrode of A2, wherein the mass fraction of the inorganicparticles in the separator layer is greater than 99%.

A4. The electrode of A0 or A1, wherein the separator layer furthercomprises a polymer mixed with the inorganic particles, such that a massfraction of the inorganic particles in the separator layer is less than50% and a mass fraction of the polymer is greater than 50%.

A5. The electrode of any one of paragraphs A0 through A4, furthercomprising a layer of polyolefin disposed on the separator layer, suchthat the separator layer is between the layer of polyolefin and theelectrode material composite.

A6. The electrode of any one of paragraphs A0 through A5, wherein theplurality of inorganic particles comprise a ceramic material.

B0. An electrochemical cell electrode having an integrated separatorlayer, the electrode comprising:

an electrochemical cell electrode having a current collector substratecoupled to one or more active material layers each comprising arespective plurality of active material particles; and

a separator layer in direct contact with an adjacent layer of the one ormore active material layers, such that the one or more active materiallayers are between the separator layer and the current collectorsubstrate, the integrated separator layer including a plurality ofceramic particles;

wherein an interlocking region secures the separator layer to theadjacent active material layer, the interlocking region including anon-planar boundary between the separator layer and the adjacent activematerial layer, such that the adjacent active material layer and theseparator layer are interpenetrated.

B1. The electrode of B0, wherein the non-planar boundary comprises aplurality of substantially discrete first fingers of the active materialparticles interlocked with a plurality of substantially discrete secondfingers of the ceramic particles.

B2. The electrode of B0 or B1, comprising only a single active materiallayer extending from the current collector substrate to the separatorlayer.

B3. The electrode of any one of paragraphs B0 through B2, wherein a massfraction of the ceramic particles in the separator layer is greater than50%.

B4. The electrode of B3, wherein the mass fraction of the ceramicparticles in the separator layer is greater than 99%.

B5. The electrode of any one of paragraphs B0 through B2, wherein theseparator layer further comprises a polymer mixed with the ceramicparticles, such that a mass fraction of the ceramic particles in theseparator layer is less than 50% and a mass fraction of the polymer isgreater than 50%.

B6. The electrode of any one of paragraphs B0 through B5, furthercomprising a layer of polyolefin disposed on the separator layer, suchthat the separator layer is between the layer of polyolefin and the oneor more active material layers.

B7. The electrode of any one of paragraphs B0 through B6, wherein theplurality of ceramic particles consist of an aluminum oxide.

C0. An electrode comprising:

an electrochemical cell electrode including a current collectorsubstrate and an electrode material composite layered onto the currentcollector substrate, wherein the electrode material composite comprisesan active material layer layered onto the current collector substrate,the active material layer including a plurality of first active materialparticles adhered together by a first binder;

an integrated separator layer layered onto the active material layer,such that the active material layer is between the separator layer andthe current collector substrate, the integrated separator layerincluding a plurality of ceramic particles adhered together by a secondbinder; and

an interlocking region configured to secure the active material layer tothe integrated separator layer, the interlocking region including anon-planar boundary between the active material layer and the integratedseparator layer, such that the active material layer and the integratedseparator layer are interpenetrated;

wherein the non-planar boundary comprises a plurality of substantiallydiscrete first fingers of the first active material particlesinterlocked with a plurality of substantially discrete second fingers ofthe ceramic particles.

D0. An electrode comprising:

an electrochemical cell electrode including a current collectorsubstrate and an electrode material composite layered onto the currentcollector substrate, wherein the electrode material composite comprisesa first layer including a plurality of first active material particles;

a second layer including a plurality of ceramic separator particles,such that the first layer is between the second layer and the currentcollector substrate; and an interlocking region adhering the first layerto the second layer, the interlocking region including a non-planarinterpenetration of the first and second layers in which first fingersof the first layer interlock with second fingers of the second layer.

D. Illustrative Electrode Manufacturing Method

The following describes steps of an illustrative method 400 for formingan electrode including multiple layers; see FIGS. 5-9 .

Aspects of electrodes and manufacturing devices described herein may beutilized in the method steps described below. Where appropriate,reference may be made to components and systems that may be used incarrying out each step. These references are for illustration, and arenot intended to limit the possible ways of carrying out any particularstep of the method.

FIG. 5 is a flowchart illustrating steps performed in an illustrativemethod, and may not recite the complete process or all steps of themethod. Although various steps of method 400 are described below anddepicted in FIG. 5 , the steps need not necessarily all be performed,and in some cases may be performed simultaneously, or in a differentorder than the order shown.

Step 402 of method 400 includes providing a substrate, wherein thesubstrate includes any suitable structure and material configured tofunction as a conductor in a secondary battery of the type describedherein. In some examples, the substrate comprises a current collector.In some examples, the substrate comprises a metal foil. The term“providing” here may include receiving, obtaining, purchasing,manufacturing, generating, processing, preprocessing, and/or the like,such that the substrate is in a state and configuration for thefollowing steps to be carried out.

Method 400 next includes a plurality of steps in which at least aportion of the substrate is coated with an electrode material composite.This may be done by causing a current collector substrate and anelectrode material composite dispenser to move relative to each other,by causing the substrate to move past an electrode material compositedispenser (or vice versa) that coats the substrate as described below.The composition of material particles in each electrode materialcomposite layer may be selected to achieve the benefits,characteristics, and results described herein. The electrode materialcomposite may include one or more electrode layers, including aplurality of active material particles, and one or more separatorlayers, each including a plurality of inorganic material particles.

FIGS. 6-8 depict electrode layers and a separator layer formed on asubstrate in various illustrative configurations, depicting how amanufactured electrode may be arranged on a web as a function ofrelative motion between the current collector substrate and theelectrode material composite dispenser.

FIG. 6 depicts a substrate web 602 having an electrode layer 604 applieddirectly to the substrate web and a separator layer 606 disposed on topof the electrode layer. The electrode layer may comprise one activematerial layer or two or more active material layers. The layersdisposed on the substrate in this manner facilitate electrode blanking,in which the conductive substrate, electrode layer, and separator layermay be cut from the web in one piece. An electrode cut in thisembodiment of the manufacturing method may have a shape 608, includingan electrode body 610 and tab 612. This may allow for a simplermanufacturing process and further reduce cost of manufacturingelectrodes.

FIG. 7 is an example of how a similar concept can be used to coatmultiple lanes simultaneously. A multiple lane configuration may be usedfor blanking electrodes for use in pouch cells as well as for use inwound cells wherein a foil region is left unslit for tabbing. Thisconfiguration may be suitable for high power applications. In thisembodiment, substrate web 702 may have electrode layer 704 applieddirectly to the substrate web and a separator layer 706 disposed on topof the electrode layer. The electrode layer may comprise one activematerial layer or two or more active material layers. In thisembodiment, electrode body 710 may have a shape 708, which is defined byan edge 712 of the separator layer 706.

FIG. 8 further depicts how a “skip coating” method of manufacture may beimplemented. In this embodiment, an electrode layer 804 may be appliedto a substrate web 802 so that electrode layer 804 has a first shape808. A separator layer 806 may be applied on a top surface of electrodelayer 804 so that separator layer 806 has a second shape 810. Firstshape 808 of electrode layer 804 may have a first width and a firstlength. Second shape 810 of separator layer 806 may have a second widthgreater than the first width and a second length greater than the firstlength. During manufacture, this may be implemented by terminatingcoating of the separator layer later and initiating coating of theseparator layer earlier than the coating of the active electrode layer.This ensures the outside edges of the active material layers are fullycovered by the separator layer prior to electrode blanking.

Step 404 of method 400 includes coating a first layer of a compositeelectrode on a first side of the substrate. In some examples, the firstlayer may include a plurality of first particles adhered together by afirst binder, the first particles having a first average particle size(or other first particle distribution). In some examples, the pluralityof first particles may comprise a plurality of first active materialparticles. In some examples, the composite electrode is an anodesuitable for inclusion within an electrochemical cell. In this case, thefirst particles may comprise graphite (artificial or natural), hardcarbon, titanate, titania, transition metals in general, elements ingroup 14 (e.g., carbon, silicon, tin, germanium, etc.), oxides,sulfides, transition metals, halides, and chalcogenides. In someexamples, the composite electrode is a cathode suitable for inclusionwithin an electrochemical cell. In this case, the first particles maycomprise transition metals (for example, nickel, cobalt, manganese,copper, zinc, vanadium, chromium, iron), and their oxides, phosphates,phosphites, and silicates. The cathode active material particles mayalso include alkalines and alkaline earth metals, aluminum, aluminumoxides and aluminum phosphates, as well as halides and chalcogenides.

The coating process of step 404 may include any suitable coatingmethod(s), such as slot die, blade coating, spray-based coating,electrostatic jet coating, or the like. In some examples, the firstlayer is coated as a wet slurry of solvent, e.g., water or NMP(N-Methyl-2-pyrrolidone), binder, conductive additive, and activematerial. In some examples, the first layer is coated dry, as an activematerial with a binder and/or a conductive additive. Step 404 mayoptionally include drying the first layer of the composite electrode.

Step 406 of method 400 includes coating a second layer onto the firstlayer, forming a multilayered (e.g., stratified) structure. The secondlayer may include a plurality of second particles adhered together by asecond binder, the second particles having a second average particlesize (or other second particle distribution). In this example, thesecond layer comprises particles configured to function as a separatorfor the electrode. For example, the second layer may comprise ceramicparticles, such as aluminum oxide (i.e., alumina (α-Al₂O₃)), corundum,calcined, tabular, synthetic boehmite, silicon oxides or silica,zirconia, and/or the like.

In some examples, steps 404 and 406 may be performed substantiallysimultaneously. For example, both of the slurries may be extrudedthrough their respective orifices simultaneously. This forms a two-layerslurry bead and coating on the moving substrate. In some examples,difference in viscosities, difference in surface tensions, difference indensities, difference in solids contents, and/or different solvents usedbetween the first active material slurry and the second separator slurrymay be tailored to cause interpenetrating finger structures at theboundary between the two composite layers. In some embodiments, theviscosities, surface tensions, densities, solids contents, and/orsolvents may be substantially similar. Creation of interpenetratingstructures, if desired, may be facilitated by turbulent flow at the wetinterface between the first active material slurry and the secondseparator slurry, creating partial intermixing of the two slurries.

To facilitate proper curing in the drying process, the first layer(closest to the current collector) may be configured (in some examples)to be dried from solvent prior to the second layer (further from thecurrent collector) so as to avoid creating skin-over effects andblisters in the resulting dried coatings.

In some examples, any of the described steps may be repeated to formthree or more layers. For example, an additional layer or layers mayinclude active materials to form a multilayered electrode structurebefore adding the separator layer. Any method described herein to impartstructure between the first active material layer and the separatorcoating may be utilized to form similar structures between anyadditional layers deposited during the manufacturing process.

Method 400 may further include drying the composite electrode in step408, and/or calendering the composite electrode. Both the first andsecond layers may experience the drying process and the calenderingprocess as a combined structure. In some examples, step 408 may becombined with calendering (e.g., in a hot roll process). In someexamples, drying step 408 includes a form of heating and energytransport to and from the electrode (e.g., convection, conduction,radiation) to expedite the drying process. In some examples, calenderingis replaced with another compression, pressing, or compaction process.In some examples, calendering the electrode may be performed by pressingthe combined first and second layers against the substrate, such thatelectrode density is increased in a non-uniform manner, with the firstlayer having a first porosity and the second layer having a lower secondporosity.

FIG. 9 shows an electrode undergoing the calendering process, in whichparticles in a second layer 906 (AKA the separator layer) can becalendered with a first layer 904 (AKA the active material layer). Thismay prevent a “crust” formation on the electrode, specifically on theactive material layer. A roller 910 may apply pressure to a fullyassembled electrode 900. Electrode 900 may include first layer 904 andsecond layer 906 applied to a substrate web 902. First layer 904 mayhave a first uncompressed thickness 912 and second layer 906 may have asecond uncompressed thickness 914 prior to calendering. After theelectrode has been calendered, first layer 904 may have a firstcompressed thickness 916 and second layer 906 may have a secondcompressed thickness 918. In some embodiments, second layer 906 may havea greater resistance to densification and a lower compressibility thanfirst layer 904. After a certain level of densification, a highertolerance to bulk compression of the separator layer may transfer a loadto the more compressible electrode layer below. This process mayeffectively densify the anode without over densifying the separatorlayer.

E. Illustrative Manufacturing System

Turning to FIG. 10 , an illustrative manufacturing system 1400 for usewith method 400 will now be described. In some examples, a slot-diecoating head with at least two fluid slots, fluid cavities, fluid lines,and fluid pumps may be used to manufacture a battery electrode featuringan active material layer and an integrated separator layer (AKA aseparator coating). In some examples, additional cavities may be used tocreate additional active material layers.

In system 1400, a foil substrate 1402 is transported by a revolvingbacking roll 1404 past a stationary dispenser device 1406. Dispenserdevice 1406 may include any suitable dispenser configured to evenly coatone or more layers of slurry onto the substrate. In some examples, thesubstrate may be held stationary while the dispenser head moves. In someexamples, both may be in motion. Dispenser device 1406 may, for example,include a dual chamber slot die coating device having a coating head1408 with two orifices 1410 and 1412. A slurry delivery system maysupply two different slurries to the coating head under pressure. Due tothe revolving nature of backing roll 1404, material exiting the lowerorifice or slot 1410 will contact substrate 1402 before material exitingthe upper orifice or slot 1412. Accordingly, a first layer 1414 will beapplied to the substrate and a second layer 1416 will be applied on topof the first layer. In the present disclosure, the first layer 1414 maybe the active material of an electrode and the second layer may be aseparator layer.

Manufacturing method 400 may be performed using a dual-slotconfiguration, as described above, to simultaneously extrude theelectrode material and the separator layers, or a multi-slotconfiguration with three or more dispensing orifices used tosimultaneously extrude a multilayered electrode with an integratedseparator layer. In some embodiments, manufacturing system 1400 mayinclude a tri-slot configuration, such that a first active materiallayer, a second active material layer, and the separator layer may allbe extruded simultaneously. In another embodiment, the separator layermay be applied after the electrode (single layered or multilayered) hasfirst dried.

Additional aspects and features of manufacturing systems and methods forelectrodes having integrated ceramic separators are presented below,without limitation, as a series of interrelated paragraphs.

E0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

causing a current collector substrate and an electrode materialcomposite dispenser to move relative to each other; and

coating at least a portion of the current collector substrate with anelectrode material composite and a separator material to produce anelectrochemical cell electrode, using the dispenser, wherein coatingincludes:

-   -   dispensing one or more active material layers each comprising a        slurry of active material composite onto the current collector        substrate using one or more respective first orifices of the        dispenser; and    -   dispensing a separator layer onto the one or more active        material layers while the active material composite is wet,        using one or more second orifices of the dispenser, such that        the one or more active material layers are between the separator        layer and the current collector substrate, the separator layer        including a plurality of ceramic particles;    -   wherein an interpenetrating boundary is formed between the        separator layer and an adjacent one of the one or more active        material layers.

E1. The method of E0, wherein the electrode material composite dispensercomprises a slot-die coating head dispenser having a plurality ofdispensing slots.

E2. The method of E0 or E1, wherein the interpenetrating boundary isformed by an interlocking region coupling the separator layer to theadjacent one of the one or more active material layers, the interlockingregion including an interpenetration in which first fingers of theseparator layer interlock with second fingers of the active materialcomposite.

E3. The method of any one of paragraphs E0 through E2, wherein the oneor more active material layers include a first layer having a pluralityof first active material particles, and a second layer having aplurality of second active material particles.

E4. The method of any one of paragraphs E0 through E3, furthercomprising calendering the electrode after the one or more activematerial layers and the separator layer have dried.

F0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

causing a current collector substrate and an electrode materialcomposite dispenser to move relative to each other; and

coating at least a portion of the current collector substrate with anelectrode material composite to produce an electrochemical cellelectrode, using the dispenser, wherein coating includes:

applying a first layer to the current collector substrate using a firstorifice of the dispenser, the first active material layer including afirst active material composite slurry having a plurality of firstactive material particles and a first binder;

applying a second layer to the first active material layer while thefirst active material layer is wet, using a second orifice of thedispenser, the second layer including a separator material slurry havinga plurality of ceramic particles and a second binder; and

forming an interlocking region adhering the first layer to the secondlayer, the interlocking region including an interpenetration of thefirst layer and the second layer in which first fingers of the firstlayer interlock with second fingers of the second layer.

G0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

applying a first layer of a first active material composite slurry to afoil substrate using a first fluid slot of a slot-die coating headdispenser, wherein the first active material composite slurry comprisesa plurality of first active material particles and a first binder; and

applying a second layer of a separator material slurry to the firstlayer while the first layer is wet, using a second slot of the slot-diecoating head dispenser, wherein the separator material slurry comprisesa plurality of inorganic particles and a second binder;

wherein an interpenetrating boundary layer is formed between the firstlayer and the second layer.

H0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

causing relative motion between a separator material dispenser and acurrent collector substrate on which is disposed a first layer of activematerial composite, wherein the first layer includes a plurality offirst active material particles and a first binder; and

applying a second layer of separator material onto the first layer,using an orifice of the dispenser, the second layer including aseparator material slurry having a plurality of ceramic particles and asecond binder;

wherein applying the second layer of separator material slurry forms aninterlocking region adhering the first layer to the second layer, theinterlocking region including an interpenetration of the first andsecond layers in which first fingers of the first layer interlock withsecond fingers of the second layer.

I0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

causing a current collector substrate and an electrode materialcomposite dispenser to move relative to each other, wherein the currentcollector substrate is at least partially coated by an uncalenderedlayer of active material composite; and

coating at least a portion of the uncalendered layer with a separatormaterial, using an orifice of the dispenser, forming a separator layerincluding a plurality of inorganic (e.g., ceramic) particles; and

forming an interlocking region adhering the separator layer to the layerof active material composite, the interlocking region including aninterpenetrating boundary layer between the inorganic particles and theactive material composite.

J0. A method of manufacturing an electrode for an electrochemical cell,the method comprising:

applying a first layer of a first active material composite slurry to afoil substrate, wherein the first active material composite slurrycomprises a plurality of first active material particles and a firstbinder; and

applying a second layer of a separator material slurry to the firstlayer before calendering, using a slot of a slot-die coating headdispenser, wherein the separator material slurry comprises a pluralityof ceramic particles and a second binder;

wherein an interpenetrating boundary layer is formed between the firstlayer and the second layer.

F. Illustrative Electrochemical Bilayer Cells with Integrated Separator

FIGS. 11, 12, and 13 depict examples of electrochemical bilayer cellsincluding electrodes with integrated separators. Aspects of electrodesand manufacturing devices described herein may be utilized as componentsof the electrochemical bilayer cells described below.

FIG. 11 depicts an example of a stacked cell configuration 1100. Abilayer cell 1110 may be formed by two electrodes (e.g., an anode 1102and a cathode 1104). One or both of anode 1102 and cathode 1104 may bemulti-layered, similar to electrode 300 of FIG. 4 . Depending on theapplication, a plurality of bilayer cells may be configured to form thestacked cells. In some embodiments, a first and last electrode in a cellincluding n electrodes may be anodes 1102. In a stacked cell format1100, anode 1102 may be configured to be longer than cathode 1104 by adistance 1106. Distance 1106 may be such that the distal ends of anode1102 extend further than the distal ends of cathode 1104. The increasedlength of the anode may help prevent shorting between the twoelectrodes. In the present example, anode 1102 may include an integratedseparator layer 1108. A similar configuration may be used for woundcells. In the case of wound cells, a single bilayer cell is formed usingany of the methods described herein, after which the bilayer cell iswound or rolled.

FIG. 12 shows a stacked cell configuration 1200 having tabs 1210 and1212 protruding from an anode 1202 and a cathode 1204 respectively, in abilayer cell 1220. One or both of anode 1202 and cathode 1204 may bemulti-layered, similar to electrode 300 of FIG. 4 . Tab 1210, in thepresent example, may protrude from anode 1202, passing through electrodelayer 1205 and separator layer 1206. A thicker separator layer 1206 onthe distal end of the electrode where the tab protrudes may preventshorting between anode 1202 and cathode 1204.

FIG. 13 shows a stacked cell configuration 1300 having tabs 1310 and1312 protruding from an anode 1302 and a cathode 1304 respectively, in abilayer cell 1320. One or both of anode 1302 and cathode 1304 may bemulti-layered, similar to electrode 300 of FIG. 4 . Tab 1310, in thepresent example, may protrude from anode 1302, passing through electrodelayer 1305 and separator layer 1306. A thicker separator layer 1306 onthe distal end of the electrode where the tab protrudes may preventshorting between anode 1302 and cathode 1304. Tape 1314 may be appliedto cathode 1304 and tab 1312 at the distal end of the electrode, furtheradding insulation and preventing shorting between anode 1302 and cathode1304.

Advantages, Features, and Benefits

The different embodiments and examples of the electrode including anintegrated ceramic separator described herein provide several advantagesover known solutions for manufacturing an electrochemical cell includinga separator. For example, illustrative embodiments and examplesdescribed herein allow for the separator and the other composite layersof the electrode to be manufactured simultaneously. Where known methodsof manufacturing require the separator to be manufactured independentlyfrom the electrode, the methods and systems described in the presentdisclosure simplify the manufacturing process by facilitatingsimultaneous manufacturing.

Additionally, and among other benefits, illustrative embodiments andexamples described herein allow for a more robust interface between theseparator layer and the active material layer on which the separator isdisposed. The non-planar interface between the two layers may bemanufactured such that there is a plurality of fingers interlocking thelayers together. This may provide the electrode with more stability andmay reduce interfacial resistance while increasing ion mobility throughthe electrode. Additionally, this provides the separator layer increasedresistance to shrinking upon reaching elevated temperatures, such as ina thermal runaway event.

No known system or device can provide the benefits of the integratedseparator layer as described herein. The simplification of themanufacturing process, as well as the functional advantages describedabove, provide a substantial improvement to known methods formanufacturing electrodes. Thus, the illustrative embodiments andexamples described herein are particularly useful for manufacturingelectrodes for use in electrochemical cells. However, not allembodiments and examples described herein provide the same advantages orthe same degree of advantage.

CONCLUSION

The disclosure set forth above may encompass multiple distinct exampleswith independent utility. Although each of these has been disclosed inits preferred form(s), the specific embodiments thereof as disclosed andillustrated herein are not to be considered in a limiting sense, becausenumerous variations are possible. To the extent that section headingsare used within this disclosure, such headings are for organizationalpurposes only. The subject matter of the disclosure includes all noveland nonobvious combinations and subcombinations of the various elements,features, functions, and/or properties disclosed herein. The followingclaims particularly point out certain combinations and subcombinationsregarded as novel and nonobvious. Other combinations and subcombinationsof features, functions, elements, and/or properties may be claimed inapplications claiming priority from this or a related application. Suchclaims, whether broader, narrower, equal, or different in scope to theoriginal claims, also are regarded as included within the subject matterof the present disclosure.

What is claimed is:
 1. An electrochemical cell electrode having anintegrated separator layer, the electrode comprising: an electrochemicalcell electrode including a current collector substrate and an electrodematerial composite including a plurality of first active materialparticles layered onto the current collector substrate, the first activematerial particles having a first average particle size; a separatorlayer including a plurality of inorganic particles, disposed such thatthe electrode material composite is between the separator layer and thecurrent collector substrate, the inorganic particles having a secondaverage particle size; and an interlocking region adhering the separatorlayer to the electrode material composite, the interlocking regionincluding a non-planar interpenetration of the separator layer and theelectrode material composite in which first irregular fingers of theelectrode material composite interlock and are three-dimensionallyinterdigitated with second irregular fingers of the separator layer;wherein a length of the first fingers is greater than twice the firstaverage particle size or twice the second average particle size,whichever is smaller; and wherein a total thickness of the interlockingregion is greater than the length of the first fingers.
 2. The electrodeof claim 1, wherein the electrode material composite comprises a firstlayer including the plurality of first active material particles, and asecond layer including a plurality of second active material particles.3. The electrode of claim 1, wherein a mass percent of the inorganicparticles in the separator layer is greater than 50%.
 4. The electrodeof claim 3, wherein the mass percent of the inorganic particles in theseparator layer is greater than 99%.
 5. The electrode of claim 1,wherein the separator layer further comprises a polymer mixed with theinorganic particles, such that a mass fraction of the inorganicparticles in the separator layer is less than 50% and a mass fraction ofthe polymer is greater than 50%.
 6. The electrode of claim 1, furthercomprising a layer of polyolefin disposed on the separator layer, suchthat the separator layer is between the layer of polyolefin and theelectrode material composite.
 7. The electrode of claim 1, wherein theplurality of inorganic particles comprise a ceramic material.
 8. Anelectrochemical cell electrode having an integrated separator layer, theelectrode comprising: an electrochemical cell electrode having a currentcollector substrate coupled to one or more active material layers eachcomprising a respective plurality of active material particles, theactive material particles having a first average particle size; and aseparator layer in direct contact with an adjacent layer of the one ormore active material layers, such that the one or more active materiallayers are between the separator layer and the current collectorsubstrate, the integrated separator layer including a plurality ofceramic particles, the ceramic particles having a second averageparticle size; wherein an interlocking region secures the separatorlayer to the adjacent active material layer, the interlocking regionincluding a non-planar boundary between the separator layer and theadjacent active material layer, such that the adjacent active materiallayer and the separator layer are interpenetrated; wherein thenon-planar boundary comprises a plurality of substantially discreteirregular first fingers of the active material particles interlocked andthree-dimensionally interdigitated with a plurality of substantiallydiscrete irregular second fingers of the ceramic particles; wherein alength of the first fingers is greater than twice the first averageparticle size or twice the second average particle size, whichever issmaller; and wherein a total thickness of the interlocking region isgreater than the length of the first fingers.
 9. The electrode of claim8, comprising only a single active material layer extending from thecurrent collector substrate to the separator layer.
 10. The electrode ofclaim 8, wherein a mass percent of the ceramic particles in theseparator layer is greater than 50%.
 11. The electrode of claim 10,wherein the mass percent of the ceramic particles in the separator layeris greater than 99%.
 12. The electrode of claim 8, wherein the separatorlayer further comprises a polymer mixed with the ceramic particles, suchthat a mass fraction of the ceramic particles in the separator layer isless than 50% and a mass fraction of the polymer is greater than 50%.13. The electrode of claim 8, further comprising a layer of polyolefindisposed on the separator layer, such that the separator layer isbetween the layer of polyolefin and the one or more active materiallayers.
 14. The electrode of claim 8, wherein the plurality of ceramicparticles consist of an aluminum oxide.